Preparation of herbs: "Studying herbs in their essence allows you to support your inner nature and destiny….All those who study the Dao must penetrate herbal lore. If you do not do so, you have no means to support the Dao." (see article 4 in full)- Wang Chongyang's teaching cited in The Taoist Experience,​ 1993 State University of New York, Albany, NY (see appendix in: http://www.itmonline.org/arts/madanyang.htm )